Answer:
The membrane potential is maintained in the cell due to the unequal distribution of the ions inside and outside of the cell. This membrane potential is important for the conduction of the nerve impulse.
The arrival of the stimulus triggers the action potential. The resting membrane potential is -70mV. This is maintained by the presence of potassium ions. The influx of the sodium ions result in the change in the membrane potential from -70mV to +30mV.
I believe it’s the lithosphere
Sea floor sediment provide an invaluable key to past climate change. Finely varved sediments from areas of rapid deposition provide a high-resolution record of past climate variation, and volcanic ash layers contribute to the comprehensive study of climate change on relatively short timescales. Oceanographers like to say that we know more about the dark side of the Moon than we do about the oceans. That statement is doubly true of the seafloor. Although modern technology has allowed us to learn more about the seafloor, vast regions remain unexplored. Scuba divers can only dive to about 40 meters and they cannot stay down there for very long. Although this is good for researching the organisms and ecosystems very near a coast, most oceanic research requires accessing greater depths.
Anything prokaryotic doesn't contain a nucleus
The outer ring is is the ever first ring but the inner ones tell if it’s old or not.